Reflector projection lamp



Oct. 13, 1936. T. o. HALL REFLECTOR PROJECTION LAMP Filed Feb. 3 1954 3Sheets-Sheet 1 INVENTOR fi m/209E Y HALL iw /j IS ATTORNEY Oct. 13,1936. Q HALL 2,057,644

REFLECTOR PROJECTION LAMP Filed Feb. 3, 1954 3 Sheets-Sheet 2 mlohh l6INV ENTOR 7Z/E000RE HALL JZLZMQMMM HIS A ORNEY Oct. 13, 1936. T. o. HALL2,057,644

REFLECTOR PROJECTION LAMP Filed Feb. 3, 1934 3 Sheets-Sheet 3 VIII/1301AO Z.- T r:

il I) II II II) II II II Illlllllll INVENTOR ZZ/EoDORE HALL PatentedOct. 13, 1936 2,057,644 REFLECTOR PROJECTION LAMP Theodore 0. Hall, WestLos Angeles, Calif., as-

signoito Hall & Connolly, Inc., New York, N. Y., a corporation of NewYork Application February 3, 1934, Serial No. 709,658

8 Claims.

This invention relates to projector lamps especially adapted for theprojection of motion pictures. The high intensity flaming arc light hascome into use for such lamps to a great extent on account of its highintrinsic brilliancy but complications, high cost and the heavy currentused in most of such lamps have militated against its use in the smallerplayhouses. One object of this invention is to devise a high intensityprojection lamp of moderate current consumption and extremely simple andinexpensive design. By pointing the positive electrode away from theprojector lens and employing a reflector, the quantity of light on thescreen may be greatly increased. I have also simplified the constructionof the standard high intensity, lamp by eliminating the rotation of thepositive electrode which has enabled me to greatly reduce the size ofthe positive electrode holder thereby decreasing the shadow castthereby.

A further improvement accomplished by my invention is the rotation ofthe reflector whereby uneven heating of the same is avoided and also thebad effects of flaws in the surface of the reflector substantiallyreduced.

Referring to the drawings showing a preferred form of my invention,

Fig.1 is a side elevation, partly in section, of my improved projectorlamp unit with the hous- 30 ing omitted.

' Fig. 2 is a rear elevation of the same.

Fig. 3 is a horizontal section taken through the negative holder.

Fig. 4 is a detail of the feeding means for one 35 of the electrodes.

Fig. 5 is a section 5-5 of Fig. 4

Fig. 6 is a rear face view of the reflector rotating gear.

Fig. '7 is a vertical section taken on line 1-1 of Fig. 6.

Fig. 8 is a front view of the feed rollers for the positive electrode. r

The lamp structure is shown as comprising a taken approximately on line45 back or baseplate l, to the outside of which is secured the lampoperating mechanism including the driving motor 2 and the blower 3driven therefrom. Detachably secured to the inside of said plate is thesupporting framework 4 of the lamp 50 proper. Said framework is shown ashollow and engages at its rear end the end of the insulated tube 5projecting from the blower so that air is discharged therefrom throughthe hollow framework. On top of said framework are mounted l5 bracket 6and bearing blocks 1 and I, said blocks having journalled therein aplurality of sleeves supporting the negative electrode 8. Next to saidelectrode is shown a split sleeve 9 which is caused to tightly grip theelectrode at its forward end by inclined surfaces thereon which areengaged by the inner tapered surface of the second sleeve l0, saidsleeve being threaded at its rear end in a sleeve ll pinned to the innersleeve 9 so that the outer sleeve may be rotated and drawn rearwardlywith respect to the inner sleeve to tightly clamp the electrode. Theouter sleeve I0 is also shown as provided with rack teeth l2 at one sidethereof with which mesh the teeth of a pinion l3 on a vertical shaft Mfor feeding the negative electrode. A striking knob 11 is also shown onthe outer end of said sleeve. To strike the arc, knob IT is pushedinwardly to contact the electrodes. This winds up torsion spring 80connecting the upper and lower parts of shaft l4 until lugs 8| and 82 oncollars 83 and 84 contact. Upon release of the knob, the spring unwindsand draws the arc.

I show the negative electrode holder as projecting through an aperturein the center of the reflector I 3. As shown, the reflector is tightlyclamped at its center between a flanged nut l4 and a flanged sleeve I5with suitable shock and heat absorbing washers l6, l6 therebetween. The

sleeve I5 is sho'wn as rotatably mounted in bracket 1 and as secured tothe hub of a gear I l, which is rotated from a pinion l8 on shaft Hi. Itwill, therefore, be readily apparent that the reflector may be revolvedat any desired speed by rotating the shaft l9.

Instead of rotating the positive electrode, I maintain the symmetry anddepth of the positive crater by imparting a wabbling or rotary motion tothe tip of the negative electrode. This distributes or revolves thenegative flame around the crater of the positive electrode and preventsunequal side burning. This may be conveniently accomplished from themechanism which rotates the reflector. To this end I have shown the gearII as provided with an eccentric interior bore 20 within which isrotatably mounted the reduced end 2| of an exterior non-rotating sleeve22. Said sleeve is shown as housing the pinion l3 and is provided at itsrear end with a spherical seat 23 engaging countersunk opening in thefixed upright 6. Therefore, as gear I! is revolved it will oscillatesleeve 22 about a point in the axis of electrode 8 as a center, thusoscillating the negativeelectrode as a whole about said center andcausing the tip thereof to describe a small circle of about the diameterof the crater of the a positive electrode but without rotating eitherthe points 26 and 21 for cooling the negative holder and also at point28 where baffles 29, 29' are placed to direct a current of air over theface of the reflector to cool the same and prevent deposits thereon. Airalso passes through the passage 30 up through the hollow positive holder25 to cool the positive holder and electrode, air also emerging at iifor the same purpose.

The feeding of the positive electrode is shown as effected from a feedshaft 32 by means of a worm l3 meshing with wormwheel 34 which drives alarge gear 35 through idler 36. Gear 55 constitutes the lower feedroller and is shown as provided with a V-shaped groove 31 for thispurpose. Above said electrode is shown an upper roller 58 which may begeared to the lower roller and is held clamped against the same by meansof a spring 39 which exerts a pressure in a counterclockwise directionaround the pivot point 40. Preferably current is introduced to thepositive electrode through the feed rollers so that the usual heavycontact brushes are eliminated. In front of said rollers there ispreferably placed an insulated shield 90 to prevent the are strikingback to the rollers. A rearward supporting roller 42 may also beprovided. For operating the feed shafts, I have shownshaft 32 asconnected through universal and detachable couplings 44 to shaft 45extending through the backplate I. Similarly the negative feed shaft ll,is shown as having a wormwheel 46 on the bottom thereof operated from aworm 41 on a shaft 48 which is connected through detachable coupling 49to a shaft 50 journalled in said backplate.

Said feed shafts are preferably both operated from the same drivingmotor at proper speeds to maintain the crater of the positive electrodeat the focus of the reflector and to maintain the proper arc length. Toeffect this purpose I have shown roller or-ball clutches 52, 53(hereinafter referred to as roller grip type clutches) on the shafts,against both of which is shown a spring brake 18. Each clutch maycomprise a camshaped plate 54 (Fig. 5) having a pin 55 extendingoutwardly therefrom through cover plate 54' and entering a slot 58 (or56) in a reciprocated side rod 51 operated from a lever 58 pivoted at 55and oscillated from a connecting rod 60 connecting said lever 58 and acrank pin ii on a gear 62 rotated from the motor 2 by means such as worm83. When pin 55 is rotated counterclockwise in Fig. 4, for instance,rollers will grip the housing 53 to rotate the same. will rotate shaft50 through slip friction clutch I! which is pressed against 53 by spring81. The extent of step-by-step motion of each clutch may accurately beadjusted in infinite steps by means of threaded shafts 85 and 66 whichengage respectively stops B1 and 58 on each of cover plates 54' to limitthe back strokes of the plates 54. By this means the rates of feed ofeach electrode may be adjusted so that each is fed at the proper rate tomaintain the proper position of the positive crater and the proper arclength. For quick hand feeding, a knurled head 69 is provided for eachfeed shaft. One spring ll may be provided for returning both ratchetfeeds after actuation, the spring being shown as connected acrossbetween the two pins 55 and 55. The upper end of lever 58 is shown ascarrying a pawl 13 for rotating the ratchet 14 on the shaft 15, which iscoupled to the shaft l9 above described for rotating the reflector andoscillating the negative tip.

In accordance with the provisions of the pat ent statutes, I have hereindescribed the principle and operation of my invention, together with theapparatus which I now consider to represent the best embodiment thereof,but I desire to have it understood that the apparatus shown is onlyillustrative and that the invention can be carried out by other means.is designed to use the various features and elemerits in the combinationand relations described, some of these may be altered and others omittedwithout interfering with the more general results outlined, and theinvention extends to such use.

Having described my invention, what I claim and desire to secure byLetters Patent is:

1. In a high intensity flaming arc lamp having a positive and negativeelectrode, of a stationary holder for the positive electrode and arevolvable holder for the negative electrode for bodily revolving thetip thereof so as to describe a small circle in front of the crater ofthe positive electrode and concentric with the major axis or core of thesame, whereby a symmetrical crater is maintained.

2. In a reflector type projector lamp, a pair of electrode holders, areflector, means for rotatably mounting the same, and means for continuously rotating the same, whereby uniform cooling is secured and the illeffects of imperfections in the reflector surface overcome.

3. In a reflector type projector lamp, a pair of electrode holders, areflector, means for. rotatably mounting the same, means forcontinuously rotating the same, and means actuated by rotation of saidreflector for causing the tip of one of the electrodes to describe aclosed figure in front of the other electrode.

4. In an arc projector lamp, an electric motor for feeding bothelectrodes, a feeding shaft for each electrode, and variable speed meansconnecting said motor and each of said feed shafts comprising a pair ofroller griptype clutches, a slide rod reciprocated by said motor, andhaving a lost motion connection with each clutch, and independent meansfor varying the amount of rotation imparted to each feed shaft perstroke of said rod.

5. A variable speedfeed for an electrode of an arc lamp comprising a.source of power, a feed shaft, a roller grip type clutch connecting tosaid shaft to rotate the same step-by-step, a member reciprocated bysaid power source, having a lost motion connection to said power source,a spring for returning said clutch after each stroke, and an adjustablestop to vary the effective stroke of the clutch in inflnite steps. a

6. In a reflector arc lamp, an electrode holder comprising a fixsupport, a sleeve normally gripping the electrode, means for advancingsaid sleeve for feeding the electrode, a rotatable element around saidsleeve journalled in said sup port and having an eccentric aperturetherein, a reflector secured to and insulated from said element to berotated thereby, and an intermedi- AlSO, While it ate sleeve journalledat one end in said element and having a universal mounting at a remotepoint in said fixed support, whereby rotation of said element wabblesthe inner sleeve and the tip of the electrode.

7. In a reflector type projector lamp, a negative electrode holder, areflector rotatably mounted thereon and having a. central aperturethrough which the electrode normally projects, means for 10 insulatingthe reflector from its mounting, and

means for circulating air over the reflector for cooling the same.

8. In a reflector type projector lamp, an electrode holder comprising afixed support, a sleeve journaled therein, a reflector having a centralaperture therein clampedin said sleeve, means for continuously revolvingthe sleeve and reflector, and means for feeding an electrode throughsaid sleeve.

THEODORE O. HALL.

